And to be totally flippant–the best way to improve your child chances of getting into med school would be to move.
Move out of California.
West Virginia has 2 medical schools (Univ of West Virginia and Edwards SOM at Marshall University) and 52% of WVA residents who apply to med school get accepted at one of them.
Or Arkansas where 50% of AR state residents get accepted to the Univ of Arkansas SOM.
Or Nebraska where 43% of NE med school applicants get accepted to one of 2 med school in that state (Univ of Nebraska and Creighton).